In a processing device which sequentially conveys a sheet member from an upstream side to a downstream side and processes the sheet member, as disclosed in Patent Literature 1, a processing device is proposed which has mechanical lifters or air lifters respectively provided in stages. In the processing device of Patent Literature 1, the lifters are respectively provided in the stages. In this processing device, protruding heights of the lifters in their free states are the same. Spaces between the lifters adjacent in an advancing direction are the same. Further, widths of the lifters respectively provided in the stages are the same.